Several unseasonably dry winters have exacerbated the problem. Heavy rain and snow this year raise hopes groundwater can be replenished, at least for a while.

By Sayed Hassib

KABUL, Feb 28 (Reuters) - A growing population is straining water supplies in Afghanistan's capital, forcing those who can afford it to dig unregulated wells ever deeper to tap a falling water table.

Finding water in arid Afghanistan is virtually always a challenge, but a drop in the groundwater level in Kabul caused by overuse and drought is making it even more difficult for residents, especially the poor.

Modern Kabul was originally planned to support about 1 million people, but is now home to more than 4.6 million, according to U.S. government estimates, with people fleeing violence and seeking jobs thronging into urban centres.

Several unseasonably dry winters, with little rain and a dusting of snow, have exacerbated the problem. Heavy rain and snow this year has raised hopes that groundwater can be replenished, at least for a while.

"The increase in population and drought has resulted in a shortage of water in Kabul, so more people are demanding deeper wells to get it," said Aslam Khan, who runs a well-digging business.

Since 2001, Kabul's sprawl has expanded by nearly 2,500 square kilometres (965 square miles), according to the World Bank, with some of the poorest arrivals perched in homes on rocky hills around the city, where wells are generally non-existent.

At the base of the hills, children cluster around hand-operated pumps, filling buckets and cans before climbing back up to their homes.

"We have lots of problem in getting water," said 15-year-old Mohammad Jaweed, bent under a load for his family.

'NO SERIOUS ATTENTION'

People who can afford it usually dig a well rather than depending on the city's limited water system, but they are having to go ever deeper to reach the receding water.

The depth of a well varies across the city, but Khan said many residents are being forced to dig 10 to 20 metres (32-64 feet) deeper than in the past.

In some cases, wells have to go down 150 metres (492 feet) or more to reach clean water, at a cost of more than $5,200, he said, a price out of reach of many people.

Officials say well digging has spiralled out of control, with little or no regulation of how the ever more scarce water is exploited.

"Unfortunately there hasn't been any serious attention to this," said Hamidullah Yelani, director general of the government's Urban Water Supply and Sewerage Corporation.

In the past, residents have been banned from digging wells within 100 metres (328 feet) of each other, but wells are now routinely dug 5 to 10 metres (16-32 feet) apart, sucking ever more water from the aquifers, said Khan.

Yelani said the government was looking to implement a licensing system. The ministry of water and power did not respond to requests for comment.

Poor residents are not optimistic authorities will get a grip on the problem, at least in a way that will help them get better access.

"The government mustn't allow people to dig deep wells because it has caused many problems," said Mohammad Karim, 60, who said he was too old to carry water up to his home on a hill.

"The poor can't dig deep wells, but that doesn't mean they should die of thirst." (Writing by Josh Smith; Editing by Robert Birsel)